autocomplete: Make ContactProvider rank contacts by affinity

chrome/browser/autocomplete/contact_provider_chromeos.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_AUTOCOMPLETE_CONTACT_PROVIDER_CHROMEOS_H_
 #define CHROME_BROWSER_AUTOCOMPLETE_CONTACT_PROVIDER_CHROMEOS_H_
 
 #include <utility>
 #include <vector>
 
@@ skipping 30 matching lines @@
 
   // contacts::ContactManagerObserver overrides:
   virtual void OnContactsUpdated(Profile* profile) OVERRIDE;
 
  private:
   struct ContactData;
   typedef std::vector<ContactData> ContactDataVector;
 
   virtual ~ContactProvider();
 
+  // Returns true if |a|'s affinity is greater than |b|'s affinity.
+  static bool CompareAffinity(const ContactData& a, const ContactData& b);
+
   // Updates |contacts_| to match the contacts currently reported by
   // ContactManager.
   void RefreshContacts();
 
   // Adds an AutocompleteMatch object for |contact| to |matches_| if |contact|
   // is matched by |input|.  |input_words| is |input.text()| split on word
   // boundaries.
   void AddContactIfMatched(const AutocompleteInput& input,
                            const std::vector<string16>& input_words,
                            const ContactData& contact);
 
   // Returns an AutocompleteMatch object corresponding to the passed-in data.
   AutocompleteMatch CreateAutocompleteMatch(const AutocompleteInput& input,
                                             const ContactData& contact);
 
   base::WeakPtr<contacts::ContactManagerInterface> contact_manager_;
 
-  // Contacts through which we search.
+  // Contacts through which we search, ordered by descending affinity.
   ContactDataVector contacts_;
 
   DISALLOW_COPY_AND_ASSIGN(ContactProvider);
 };
 
 #endif  // CHROME_BROWSER_AUTOCOMPLETE_CONTACT_PROVIDER_CHROMEOS_H_